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[sanitizer] Improve FreeBSD ASLR detection
[llvm-project.git] / lldb / tools / debugserver / source / MacOSX / MachException.cpp
blobdb154d160b41ab334dae53bdb3e17d0812b22296
1 //===-- MachException.cpp ---------------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Created by Greg Clayton on 6/18/07.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "MachException.h"
14 #include "DNB.h"
15 #include "DNBError.h"
16 #include "DNBLog.h"
17 #include "MachProcess.h"
18 #include "PThreadMutex.h"
19 #include "SysSignal.h"
20 #include <cerrno>
21 #include <sys/ptrace.h>
22 #include <sys/types.h>
23
24 // Routine mach_exception_raise
25 extern "C" kern_return_t
26 catch_mach_exception_raise(mach_port_t exception_port, mach_port_t thread,
27 mach_port_t task, exception_type_t exception,
28 mach_exception_data_t code,
29 mach_msg_type_number_t codeCnt);
30
31 extern "C" kern_return_t catch_mach_exception_raise_state(
32 mach_port_t exception_port, exception_type_t exception,
33 const mach_exception_data_t code, mach_msg_type_number_t codeCnt,
34 int *flavor, const thread_state_t old_state,
35 mach_msg_type_number_t old_stateCnt, thread_state_t new_state,
36 mach_msg_type_number_t *new_stateCnt);
37
38 // Routine mach_exception_raise_state_identity
39 extern "C" kern_return_t catch_mach_exception_raise_state_identity(
40 mach_port_t exception_port, mach_port_t thread, mach_port_t task,
41 exception_type_t exception, mach_exception_data_t code,
42 mach_msg_type_number_t codeCnt, int *flavor, thread_state_t old_state,
43 mach_msg_type_number_t old_stateCnt, thread_state_t new_state,
44 mach_msg_type_number_t *new_stateCnt);
45
46 extern "C" boolean_t mach_exc_server(mach_msg_header_t *InHeadP,
47 mach_msg_header_t *OutHeadP);
48
49 // Note: g_message points to the storage allocated to catch the data from
50 // catching the current exception raise. It's populated when we catch a raised
51 // exception which can't immediately be replied to.
52 //
53 // If it becomes possible to catch exceptions from multiple threads
54 // simultaneously, accesses to g_message would need to be mutually exclusive.
55 static MachException::Data *g_message = NULL;
56
57 extern "C" kern_return_t catch_mach_exception_raise_state(
58 mach_port_t exc_port, exception_type_t exc_type,
59 const mach_exception_data_t exc_data, mach_msg_type_number_t exc_data_count,
60 int *flavor, const thread_state_t old_state,
61 mach_msg_type_number_t old_stateCnt, thread_state_t new_state,
62 mach_msg_type_number_t *new_stateCnt) {
63 if (DNBLogCheckLogBit(LOG_EXCEPTIONS)) {
64 DNBLogThreaded("::%s ( exc_port = 0x%4.4x, exc_type = %d ( %s ), exc_data "
65 "= 0x%llx, exc_data_count = %d)",
66 __FUNCTION__, exc_port, exc_type,
67 MachException::Name(exc_type), (uint64_t)exc_data,
68 exc_data_count);
69 }
70 return KERN_FAILURE;
71 }
72
73 extern "C" kern_return_t catch_mach_exception_raise_state_identity(
74 mach_port_t exc_port, mach_port_t thread_port, mach_port_t task_port,
75 exception_type_t exc_type, mach_exception_data_t exc_data,
76 mach_msg_type_number_t exc_data_count, int *flavor,
77 thread_state_t old_state, mach_msg_type_number_t old_stateCnt,
78 thread_state_t new_state, mach_msg_type_number_t *new_stateCnt) {
79 if (DNBLogCheckLogBit(LOG_EXCEPTIONS)) {
80 DNBLogThreaded("::%s ( exc_port = 0x%4.4x, thd_port = 0x%4.4x, tsk_port = "
81 "0x%4.4x, exc_type = %d ( %s ), exc_data[%d] = { 0x%llx, "
82 "0x%llx })",
83 __FUNCTION__, exc_port, thread_port, task_port, exc_type,
84 MachException::Name(exc_type), exc_data_count,
85 (uint64_t)(exc_data_count > 0 ? exc_data[0] : 0xBADDBADD),
86 (uint64_t)(exc_data_count > 1 ? exc_data[1] : 0xBADDBADD));
87 }
88
89 return KERN_FAILURE;
90 }
91
92 extern "C" kern_return_t
93 catch_mach_exception_raise(mach_port_t exc_port, mach_port_t thread_port,
94 mach_port_t task_port, exception_type_t exc_type,
95 mach_exception_data_t exc_data,
96 mach_msg_type_number_t exc_data_count) {
97 if (DNBLogCheckLogBit(LOG_EXCEPTIONS)) {
98 DNBLogThreaded("::%s ( exc_port = 0x%4.4x, thd_port = 0x%4.4x, tsk_port = "
99 "0x%4.4x, exc_type = %d ( %s ), exc_data[%d] = { 0x%llx, "
100 "0x%llx })",
101 __FUNCTION__, exc_port, thread_port, task_port, exc_type,
102 MachException::Name(exc_type), exc_data_count,
103 (uint64_t)(exc_data_count > 0 ? exc_data[0] : 0xBADDBADD),
104 (uint64_t)(exc_data_count > 1 ? exc_data[1] : 0xBADDBADD));
105 }
106 g_message->exc_type = 0;
107 g_message->exc_data.clear();
108
109 if (task_port == g_message->task_port) {
110 g_message->task_port = task_port;
111 g_message->thread_port = thread_port;
112 g_message->exc_type = exc_type;
113 g_message->AppendExceptionData(exc_data, exc_data_count);
114 return KERN_SUCCESS;
115 } else if (!MachTask::IsValid(g_message->task_port)) {
116 // Our original exception port isn't valid anymore check for a SIGTRAP
117 if (exc_type == EXC_SOFTWARE && exc_data_count == 2 &&
118 exc_data[0] == EXC_SOFT_SIGNAL && exc_data[1] == SIGTRAP) {
119 // We got a SIGTRAP which indicates we might have exec'ed and possibly
120 // lost our old task port during the exec, so we just need to switch over
121 // to using this new task port
122 g_message->task_port = task_port;
123 g_message->thread_port = thread_port;
124 g_message->exc_type = exc_type;
125 g_message->AppendExceptionData(exc_data, exc_data_count);
126 return KERN_SUCCESS;
127 }
128 }
129 return KERN_FAILURE;
130 }
131
132 void MachException::Message::Dump() const {
133 DNBLogThreadedIf(LOG_EXCEPTIONS, " exc_msg { bits = 0x%8.8x size = 0x%8.8x "
134 "remote-port = 0x%8.8x local-port = 0x%8.8x "
135 "reserved = 0x%8.8x id = 0x%8.8x } ",
136 exc_msg.hdr.msgh_bits, exc_msg.hdr.msgh_size,
137 exc_msg.hdr.msgh_remote_port, exc_msg.hdr.msgh_local_port,
138 exc_msg.hdr.msgh_reserved, exc_msg.hdr.msgh_id);
139
140 DNBLogThreadedIf(LOG_EXCEPTIONS, "reply_msg { bits = 0x%8.8x size = 0x%8.8x "
141 "remote-port = 0x%8.8x local-port = 0x%8.8x "
142 "reserved = 0x%8.8x id = 0x%8.8x }",
143 reply_msg.hdr.msgh_bits, reply_msg.hdr.msgh_size,
144 reply_msg.hdr.msgh_remote_port,
145 reply_msg.hdr.msgh_local_port, reply_msg.hdr.msgh_reserved,
146 reply_msg.hdr.msgh_id);
147
148 state.Dump();
149 }
150
151 bool MachException::Data::GetStopInfo(
152 struct DNBThreadStopInfo *stop_info) const {
153 // Zero out the structure.
154 memset(stop_info, 0, sizeof(struct DNBThreadStopInfo));
155
156 if (exc_type == 0) {
157 stop_info->reason = eStopTypeInvalid;
158 return true;
159 }
160
161 // We always stop with a mach exceptions
162 stop_info->reason = eStopTypeException;
163 // Save the EXC_XXXX exception type
164 stop_info->details.exception.type = exc_type;
165
166 // Fill in a text description
167 const char *exc_name = MachException::Name(exc_type);
168 char *desc = stop_info->description;
169 const char *end_desc = desc + DNB_THREAD_STOP_INFO_MAX_DESC_LENGTH;
170 if (exc_name)
171 desc +=
172 snprintf(desc, DNB_THREAD_STOP_INFO_MAX_DESC_LENGTH, "%s", exc_name);
173 else
174 desc +=
175 snprintf(desc, DNB_THREAD_STOP_INFO_MAX_DESC_LENGTH, "%i", exc_type);
176
177 stop_info->details.exception.data_count = exc_data.size();
178
179 int soft_signal = SoftSignal();
180 if (soft_signal) {
181 if (desc < end_desc) {
182 const char *sig_str = SysSignal::Name(soft_signal);
183 snprintf(desc, end_desc - desc, " EXC_SOFT_SIGNAL( %i ( %s ))",
184 soft_signal, sig_str ? sig_str : "unknown signal");
185 }
186 } else {
187 // No special disassembly for exception data, just
188 size_t idx;
189 if (desc < end_desc) {
190 desc += snprintf(desc, end_desc - desc, " data[%llu] = {",
191 (uint64_t)stop_info->details.exception.data_count);
192
193 for (idx = 0;
194 desc < end_desc && idx < stop_info->details.exception.data_count;
195 ++idx)
196 desc += snprintf(
197 desc, end_desc - desc, "0x%llx%c", (uint64_t)exc_data[idx],
198 ((idx + 1 == stop_info->details.exception.data_count) ? '}' : ','));
199 }
200 }
201
202 // Copy the exception data
203 size_t i;
204 for (i = 0; i < stop_info->details.exception.data_count; i++)
205 stop_info->details.exception.data[i] = exc_data[i];
206
207 return true;
208 }
209
210 void MachException::Data::DumpStopReason() const {
211 int soft_signal = SoftSignal();
212 if (soft_signal) {
213 const char *signal_str = SysSignal::Name(soft_signal);
214 if (signal_str)
215 DNBLog("signal(%s)", signal_str);
216 else
217 DNBLog("signal(%i)", soft_signal);
218 return;
219 }
220 DNBLog("%s", Name(exc_type));
221 }
222
223 kern_return_t MachException::Message::Receive(mach_port_t port,
224 mach_msg_option_t options,
225 mach_msg_timeout_t timeout,
226 mach_port_t notify_port) {
227 DNBError err;
228 const bool log_exceptions = DNBLogCheckLogBit(LOG_EXCEPTIONS);
229 mach_msg_timeout_t mach_msg_timeout =
230 options & MACH_RCV_TIMEOUT ? timeout : 0;
231 if (log_exceptions && ((options & MACH_RCV_TIMEOUT) == 0)) {
232 // Dump this log message if we have no timeout in case it never returns
233 DNBLogThreaded("::mach_msg ( msg->{bits = %#x, size = %u remote_port = "
234 "%#x, local_port = %#x, reserved = 0x%x, id = 0x%x}, option "
235 "= %#x, send_size = 0, rcv_size = %llu, rcv_name = %#x, "
236 "timeout = %u, notify = %#x)",
237 exc_msg.hdr.msgh_bits, exc_msg.hdr.msgh_size,
238 exc_msg.hdr.msgh_remote_port, exc_msg.hdr.msgh_local_port,
239 exc_msg.hdr.msgh_reserved, exc_msg.hdr.msgh_id, options,
240 (uint64_t)sizeof(exc_msg.data), port, mach_msg_timeout,
241 notify_port);
242 }
243
244 err = ::mach_msg(&exc_msg.hdr,
245 options, // options
246 0, // Send size
247 sizeof(exc_msg.data), // Receive size
248 port, // exception port to watch for exception on
249 mach_msg_timeout, // timeout in msec (obeyed only if
250 // MACH_RCV_TIMEOUT is ORed into the
251 // options parameter)
252 notify_port);
253
254 // Dump any errors we get
255 if (log_exceptions) {
256 err.LogThreaded("::mach_msg ( msg->{bits = %#x, size = %u remote_port = "
257 "%#x, local_port = %#x, reserved = 0x%x, id = 0x%x}, "
258 "option = %#x, send_size = %u, rcv_size = %u, rcv_name = "
259 "%#x, timeout = %u, notify = %#x)",
260 exc_msg.hdr.msgh_bits, exc_msg.hdr.msgh_size,
261 exc_msg.hdr.msgh_remote_port, exc_msg.hdr.msgh_local_port,
262 exc_msg.hdr.msgh_reserved, exc_msg.hdr.msgh_id, options, 0,
263 sizeof(exc_msg.data), port, mach_msg_timeout, notify_port);
264 }
265 return err.Status();
266 }
267
268 bool MachException::Message::CatchExceptionRaise(task_t task) {
269 bool success = false;
270 state.task_port = task;
271 g_message = &state;
272 // The exc_server function is the MIG generated server handling function
273 // to handle messages from the kernel relating to the occurrence of an
274 // exception in a thread. Such messages are delivered to the exception port
275 // set via thread_set_exception_ports or task_set_exception_ports. When an
276 // exception occurs in a thread, the thread sends an exception message to
277 // its exception port, blocking in the kernel waiting for the receipt of a
278 // reply. The exc_server function performs all necessary argument handling
279 // for this kernel message and calls catch_exception_raise,
280 // catch_exception_raise_state or catch_exception_raise_state_identity,
281 // which should handle the exception. If the called routine returns
282 // KERN_SUCCESS, a reply message will be sent, allowing the thread to
283 // continue from the point of the exception; otherwise, no reply message
284 // is sent and the called routine must have dealt with the exception
285 // thread directly.
286 if (mach_exc_server(&exc_msg.hdr, &reply_msg.hdr)) {
287 success = true;
288 } else if (DNBLogCheckLogBit(LOG_EXCEPTIONS)) {
289 DNBLogThreaded("mach_exc_server returned zero...");
290 }
291 g_message = NULL;
292 return success;
293 }
294
295 kern_return_t MachException::Message::Reply(MachProcess *process, int signal) {
296 // Reply to the exception...
297 DNBError err;
298
299 // If we had a soft signal, we need to update the thread first so it can
300 // continue without signaling
301 int soft_signal = state.SoftSignal();
302 if (soft_signal) {
303 int state_pid = -1;
304 if (process->Task().TaskPort() == state.task_port) {
305 // This is our task, so we can update the signal to send to it
306 state_pid = process->ProcessID();
307 soft_signal = signal;
308 } else {
309 err = ::pid_for_task(state.task_port, &state_pid);
310 }
311
312 assert(state_pid != -1);
313 if (state_pid != -1) {
314 errno = 0;
315 if (::ptrace(PT_THUPDATE, state_pid,
316 (caddr_t)((uintptr_t)state.thread_port), soft_signal) != 0)
317 err.SetError(errno, DNBError::POSIX);
318 else
319 err.Clear();
320
321 if (DNBLogCheckLogBit(LOG_EXCEPTIONS) || err.Fail())
322 err.LogThreaded("::ptrace (request = PT_THUPDATE, pid = 0x%4.4x, tid = "
323 "0x%4.4x, signal = %i)",
324 state_pid, state.thread_port, soft_signal);
325 }
326 }
327
328 DNBLogThreadedIf(
329 LOG_EXCEPTIONS, "::mach_msg ( msg->{bits = %#x, size = %u, remote_port = "
330 "%#x, local_port = %#x, reserved = 0x%x, id = 0x%x}, "
331 "option = %#x, send_size = %u, rcv_size = %u, rcv_name = "
332 "%#x, timeout = %u, notify = %#x)",
333 reply_msg.hdr.msgh_bits, reply_msg.hdr.msgh_size,
334 reply_msg.hdr.msgh_remote_port, reply_msg.hdr.msgh_local_port,
335 reply_msg.hdr.msgh_reserved, reply_msg.hdr.msgh_id,
336 MACH_SEND_MSG | MACH_SEND_INTERRUPT, reply_msg.hdr.msgh_size, 0,
337 MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
338
339 err = ::mach_msg(&reply_msg.hdr, MACH_SEND_MSG | MACH_SEND_INTERRUPT,
340 reply_msg.hdr.msgh_size, 0, MACH_PORT_NULL,
341 MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
342
343 if (err.Fail()) {
344 if (err.Status() == MACH_SEND_INTERRUPTED) {
345 if (DNBLogCheckLogBit(LOG_EXCEPTIONS))
346 err.LogThreaded("::mach_msg() - send interrupted");
347 // TODO: keep retrying to reply???
348 } else {
349 if (state.task_port == process->Task().TaskPort()) {
350 DNBLogThreaded("error: mach_msg() returned an error when replying to a "
351 "mach exception: error = %u",
352 err.Status());
353 } else {
354 if (DNBLogCheckLogBit(LOG_EXCEPTIONS))
355 err.LogThreaded("::mach_msg() - failed (child of task)");
356 }
357 }
358 }
359
360 return err.Status();
361 }
362
363 void MachException::Data::Dump() const {
364 const char *exc_type_name = MachException::Name(exc_type);
365 DNBLogThreadedIf(
366 LOG_EXCEPTIONS, " state { task_port = 0x%4.4x, thread_port = "
367 "0x%4.4x, exc_type = %i (%s) ...",
368 task_port, thread_port, exc_type, exc_type_name ? exc_type_name : "???");
369
370 const size_t exc_data_count = exc_data.size();
371 // Dump any special exception data contents
372 int soft_signal = SoftSignal();
373 if (soft_signal != 0) {
374 const char *sig_str = SysSignal::Name(soft_signal);
375 DNBLogThreadedIf(LOG_EXCEPTIONS,
376 " exc_data: EXC_SOFT_SIGNAL (%i (%s))",
377 soft_signal, sig_str ? sig_str : "unknown signal");
378 } else {
379 // No special disassembly for this data, just dump the data
380 size_t idx;
381 for (idx = 0; idx < exc_data_count; ++idx) {
382 DNBLogThreadedIf(LOG_EXCEPTIONS, " exc_data[%llu]: 0x%llx",
383 (uint64_t)idx, (uint64_t)exc_data[idx]);
384 }
385 }
386 }
387
388 // The EXC_MASK_ALL value hard-coded here so that lldb can be built
389 // on a new OS with an older deployment target . The new OS may have
390 // an addition to its EXC_MASK_ALL that the old OS will not recognize -
391 // <mach/exception_types.h> doesn't vary the value based on the deployment
392 // target. So we need a known set of masks that can be assumed to be
393 // valid when running on an older OS. We'll fall back to trying
394 // PREV_EXC_MASK_ALL if the EXC_MASK_ALL value lldb was compiled with is
395 // not recognized.
396
397 #define PREV_EXC_MASK_ALL (EXC_MASK_BAD_ACCESS | \
398 EXC_MASK_BAD_INSTRUCTION | \
399 EXC_MASK_ARITHMETIC | \
400 EXC_MASK_EMULATION | \
401 EXC_MASK_SOFTWARE | \
402 EXC_MASK_BREAKPOINT | \
403 EXC_MASK_SYSCALL | \
404 EXC_MASK_MACH_SYSCALL | \
405 EXC_MASK_RPC_ALERT | \
406 EXC_MASK_RESOURCE | \
407 EXC_MASK_GUARD | \
408 EXC_MASK_MACHINE)
409
410 #define LLDB_EXC_MASK EXC_MASK_ALL
411
412 kern_return_t MachException::PortInfo::Save(task_t task) {
413 DNBLogThreadedIf(LOG_EXCEPTIONS | LOG_VERBOSE,
414 "MachException::PortInfo::Save ( task = 0x%4.4x )", task);
415 // Be careful to be able to have debugserver built on a newer OS than what
416 // it is currently running on by being able to start with all exceptions
417 // and back off to just what is supported on the current system
418 DNBError err;
419
420 mask = LLDB_EXC_MASK;
421
422 count = (sizeof(ports) / sizeof(ports[0]));
423 err = ::task_get_exception_ports(task, mask, masks, &count, ports, behaviors,
424 flavors);
425 if (DNBLogCheckLogBit(LOG_EXCEPTIONS) || err.Fail())
426 err.LogThreaded("::task_get_exception_ports ( task = 0x%4.4x, mask = 0x%x, "
427 "maskCnt => %u, ports, behaviors, flavors )",
428 task, mask, count);
429
430 if (err.Status() == KERN_INVALID_ARGUMENT && mask != PREV_EXC_MASK_ALL) {
431 mask = PREV_EXC_MASK_ALL;
432 count = (sizeof(ports) / sizeof(ports[0]));
433 err = ::task_get_exception_ports(task, mask, masks, &count, ports,
434 behaviors, flavors);
435 if (DNBLogCheckLogBit(LOG_EXCEPTIONS) || err.Fail())
436 err.LogThreaded("::task_get_exception_ports ( task = 0x%4.4x, mask = "
437 "0x%x, maskCnt => %u, ports, behaviors, flavors )",
438 task, mask, count);
439 }
440 if (err.Fail()) {
441 mask = 0;
442 count = 0;
443 }
444 return err.Status();
445 }
446
447 kern_return_t MachException::PortInfo::Restore(task_t task) {
448 DNBLogThreadedIf(LOG_EXCEPTIONS | LOG_VERBOSE,
449 "MachException::PortInfo::Restore( task = 0x%4.4x )", task);
450 uint32_t i = 0;
451 DNBError err;
452 if (count > 0) {
453 for (i = 0; i < count; i++) {
454 err = ::task_set_exception_ports(task, masks[i], ports[i], behaviors[i],
455 flavors[i]);
456 if (DNBLogCheckLogBit(LOG_EXCEPTIONS) || err.Fail()) {
457 err.LogThreaded("::task_set_exception_ports ( task = 0x%4.4x, "
458 "exception_mask = 0x%8.8x, new_port = 0x%4.4x, "
459 "behavior = 0x%8.8x, new_flavor = 0x%8.8x )",
460 task, masks[i], ports[i], behaviors[i], flavors[i]);
461 // Bail if we encounter any errors
462 }
463
464 if (err.Fail())
465 break;
466 }
467 }
468 count = 0;
469 return err.Status();
470 }
471
472 const char *MachException::Name(exception_type_t exc_type) {
473 switch (exc_type) {
474 case EXC_BAD_ACCESS:
475 return "EXC_BAD_ACCESS";
476 case EXC_BAD_INSTRUCTION:
477 return "EXC_BAD_INSTRUCTION";
478 case EXC_ARITHMETIC:
479 return "EXC_ARITHMETIC";
480 case EXC_EMULATION:
481 return "EXC_EMULATION";
482 case EXC_SOFTWARE:
483 return "EXC_SOFTWARE";
484 case EXC_BREAKPOINT:
485 return "EXC_BREAKPOINT";
486 case EXC_SYSCALL:
487 return "EXC_SYSCALL";
488 case EXC_MACH_SYSCALL:
489 return "EXC_MACH_SYSCALL";
490 case EXC_RPC_ALERT:
491 return "EXC_RPC_ALERT";
492 #ifdef EXC_CRASH
493 case EXC_CRASH:
494 return "EXC_CRASH";
495 #endif
496 case EXC_RESOURCE:
497 return "EXC_RESOURCE";
498 #ifdef EXC_GUARD
499 case EXC_GUARD:
500 return "EXC_GUARD";
501 #endif
502 #ifdef EXC_CORPSE_NOTIFY
503 case EXC_CORPSE_NOTIFY:
504 return "EXC_CORPSE_NOTIFY";
505 #endif
506 #ifdef EXC_CORPSE_VARIANT_BIT
507 case EXC_CORPSE_VARIANT_BIT:
508 return "EXC_CORPSE_VARIANT_BIT";
509 #endif
510 default:
511 break;
512 }
513 return NULL;
514 }
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